This invention relates to cannulas, and particularly to cannulas intended for insertion into the ocular cavity for purposes of regulating or maintaining humoral pressure during opthalmic surgery.
Surgical procedures involving the eyeball, particularly retinal procedures, require the introduction of one or more instruments into the eye. This results in the leakage of fluid from the interior of the eye, and in many procedures fluid is intentionally drained. Infusion cannulas are therefore used in conjunction with these instruments to maintain or regulate the fluid pressure inside the eye. While infusion lines contiguous with the other surgical instruments have been used, the use of independent infusion sites are preferred in surgical procedures in view of certain advantages which they offer.
Methods for holding the cannula in place after insertion have included vacuum attachment features and suturing. Structures utilizing vacuum require vacuum sources and close regulation of the degree of vacuum. Suturing, on the other hand, is a time-consuming procedure and aggravates the trauma in the sclera at the point of entry of the cannula.